Get-FileNameHash.ps1

$String = 'Narrator.exe'

$MemoryStream = [System.IO.MemoryStream]::new()
$StreamWriter = [System.IO.StreamWriter]::new( $MemoryStream )
$StreamWriter.write( $String )
$StreamWriter.Flush()
$MemoryStream.Position = 0
$Hash = Get-FileHash -InputStream $MemoryStream -Algorithm 'SHA1'
$HexString = '0x' + 
    $Hash.Hash.Substring( 6, 2 ) +
    $Hash.Hash.Substring( 4, 2 ) +
    $Hash.Hash.Substring( 2, 2 ) +
    $Hash.Hash.Substring( 0, 2 )

[System.uInt32]$HexString